Title:
Ten-Year Field Evaluation of Corrosion-Inhibiting Systems in Concrete Bridge Barrier Walls
Author(s):
Daniel Cusson and Shiyuan Qian
Publication:
Materials Journal
Volume:
106
Issue:
3
Appears on pages(s):
291-300
Keywords:
bridges; chloride ingress; corrosion-inhibiting systems; cracking; durability; high-performance concrete; steel corrosion; walls.
DOI:
10.14359/56554
Date:
5/1/2009
Abstract:
The performance of eight commercial corrosion-inhibiting systems was assessed in the field over 10 years on reinforced concrete barrier walls of a highway bridge that was subjected to severe environmental conditions. These systems were composed of one or more of the following components: anticorrosion concrete admixtures, reinforcement coatings, and concrete surface coatings/sealers. The field evaluation consisted of annual surveys of corrosion potential and corrosion rate, as well as visual inspections and testing of concrete cores. After 10 years, the main reinforcement of the barrier walls, at a depth of 75 mm (3 in.), was found in relatively good condition due to an initially high-quality concrete. Special bars embedded at a depth of 13 mm (1/2 in.) in the barrier walls showed signs of advanced corrosion for all systems; however, no visible signs of corrosion were found on 25 mm (1 in.) deep bars. Nondestructive corrosion evaluation over the 25 mm (1 in.) deep ladder reinforcing bars indicated that the system containing the inorganic anticorrosion admixture provided consistently lower risks of corrosion, followed by systems containing organic anticorrosion admixtures, in comparison to the control system and other systems. The low concrete permeability and different stability of the protective layer forming on the bars may explain the observed differences in the effectiveness of these systems.